This invention relates to an improved truck trailer design which incorporates the use of standard components, slightly modified, to enable enhanced maneuverability through the use of a steerable rear axle assembly. The intention modifies the design of large truck trailers to include a rear axle which may be pivotally controlled by the driver of the towing truck.
The invention addresses the need to enhance the maneuverability of large tractor trailers on highways and city streets. Increased trailer lengths may be used in areas where previously they could not be towed for lack of sufficient area to maneuver.
When a tractor towing a conventional trailer of 48 feet or more in length negotiates a sharp turn in the road, it is necessary that the tractor first swing out in a direction opposed to the desired turn. This motion ensures that when the tractor makes the turn, the trailing edge of the trailer will clear the intersection. If there is insufficient space to make this preparative maneuver, it is possible that the tractor and trailer combination may not successfully negotiate the turn. In constrictive city streets, with significant traffic, a truck and its trailer may very well disrupt the flow of traffic while attempting to turn onto a side street.
In order to back a trailer into a loading or unloading dock, significant clear space must be afforded to allow the driver of the tractor the ability to orient the rear of the trailer in the desired direction. The only steering ability enabled in a conventional tractor trailer combination is through the relative orientation of the tractor to the trailer. The addition of rear wheel steering on the trailer significantly decreases the space required to maneuver the tractor-trailer combination.
The present embodiment of the invention combines elements of several commonly available tractor trailer elements in order to achieve a cost-effective means of implementation of the invention. It is necessary to briefly discuss these elements to understand the benefits associated with the invention.
A tractor is a truck which tows a semi-trailer; the tractor having a feature, commonly referred to as a fifth wheel, which facilitates its engagement to a receptacle on the semi-trailer.
Typically, a tractor pulling one trailer will be pivotally attached to the trailer. The rear wheel assembly of the trailer is rigidly attached to the bottom of the trailer body. If an additional trailer is towed in a double configuration, so that the tractor pulls two trailers, a second trailer is attached to the rear of the first trailer. A converter dolly is used to support the front end of the second trailer, which is pivotally attached to both the first trailer and the second trailer.
The invention uses the commonly available converter dolly mounted at the rear and bottom side of a common trailer body to facilitate a steerable rear wheel assembly. Further features of the invention will be apparent from the attached drawings and description of an illustrative embodiment of the invention.